Using aging clocks on whole blood samples is problematic due to blood's dynamic nature and cell population variations.

“my worry uh when I saw the paper which is a worry that actually existed predated this u was also a worry when people were using tome tie length is the idea when you sample the blood as an iminologist I know this is a highly dynamic uh organ think about the blood as an organ we enumerate at this point today with the best technology more than 500 different populations of cells in the blood. Suppose that these cells vary in response to any intervention and that these cells individually have a different epigenetic age. You would have the impression that you are rejuvenating, you know, which is was the claim of that fee paper that they had rejuvenated people.